The invention is an 8 channel pulse height analyzer using an 8.times.32 dot light emitting diode (l.e.d) display. Various industrial personnel have expressed an interest in a device having the ability to search for the presence of a single dedicated gamma ray inside pipes, tubes, and equipment. They wished to be able to "point" a device at the area of interest and have it respond. For example, U-235 emits a 186 keV gamma that can penetrate 1/4 inch of steel and is easily detected by a NaI photomultiplier tube. Normally, presence of the 186 keV line would be indicated by use of a conventional 1024 channel pulse height analyzer, which is a laboratory piece of equipment having the ability to detect a wide range of gamma rays and not having the ability to be dedicated to a single gamma-line display. By mounting the l.e.d display on the side of the photomultiplier and by battery powering the electronics, the NaI photomultiplier tube with display becomes a wand. The presence of the gamma of interest is indicated by the growth in amplitude of the peak shape of the line on the l.e.d display. The "wand" assembly is powered and the display driven via two 1/4" diameter, 20 foot long cables coming from a 15 pound portable electronics and battery package. The concept of displaying a single gamma-line, or absorption edge, with a low cost x-y display also can be adapted to many other usages where it would aid an operator adjusting electronics to their proper setting.
Pulse height analyzers present a display of pulse-height frequency-of-occurrence versus pulse height. This is achieved by dividing the possible pulse height range into several, equal, height-segments; assigning a counter to each equal height segment; analyzing the height of each incoming pulse; and adding a count to the appropriate counter. As more and more pulses are analyzed, the pulse height frequency versus pulse-height information develops within the set of counters. Display of the pulse height information can be done concurrently with data accumulation. The content of the several counters is accumulated and plotted vertically against counter identity (i.e. pulse height) horizontally. Conventional laboratory models such as ND66 XP Transportable Multichannel Analyzer/Computer System by Nuclear Data Inc., and NS-700 Series Pulse Height Analyzer by Tracor Northern generally require more extensive technical expertise to operate and determine what particular gamma-line is present. Furthermore, experience has indicated that it is usually impractical to use such devices in an industrial setting, due to their bulk and extreme sensitivity. Moreover, conventional pulse height analyzers are typically not designed to be portable, nor are they dedicated to a single gamma-line occurrence.